1. Field of the Invention
The present invention relates to a touch input device for switching driving signals, and more particularly, to a touch input device capable of switching different driving signals in accordance with different panels with different loading capacitance.
2. Description of the Related Art
Touch panels are widely applied in a variety of fields such as personal computers, smart phones, public information stations, home appliances, and industrial control devices. The touch panels include several categories including resistive touch screen, photoelectric touch screen, ultrasonic touch screen, flat capacitive touch screen, and projected capacitive touch screen, all of which are undergoing rapid advancements in technology. However, each of these touch screen categories will have drawbacks if applied to a common display panel, as each category has been developed specifically for a particular display.
FIG. 1 is a schematic view of a conventional touch panel 10. The touch panel 10 includes a plurality of X-directional sensing lines X1 to Xm, and a plurality of Y-directional sensing lines Y1 to Yn, wherein m and n are the same positive integer or different positive integers. The X-directional sensing lines X1 to Xm and the Y-directional sensing lines Y1 to Yn are embedded in different layers of the touch panel 10. Referring to FIG. 1, the X-directional sensing lines X1 to Xm and the Y-directional sensing lines Y1 to Yn are arranged in a staggered manner, thereby forming a sensing grid. In the sensing grid, a plurality of mutual capacitors 11 (not shown) are formed between every X-directional sensing line and every Y-directional sensing line. A plurality of parasitic capacitors (e.g., having self capacitance) 13 are formed between either every X-directional sensing line or every Y-directional sensing line and the ground. During operation of the conventional touch panel, a driving signal (e.g., a square wave signal) is inputted to a sensing line in a direction (e.g., an X-directional sensing line), while a sensing line in the other direction (e.g., a Y-directional sensing line) measures the coupling signal coupled with the X-directional sensing line to detect touch gesture. Since the conventional capacitive touch input device utilizes a single driving method to detect the touch gesture, it is difficult for touch panels with different loading capacitances to be applied to a variety of electronic devices due to limited options for compatibility or a limited hardware standard.
Therefore, there is a need to provide a touch input device capable of switching driving signals in accordance with a panel with different loading capacitances to solve the above problems.